US President, Joe Biden announced Wednesday January 25, that he plans to send 31 M1 Abrams tanks to Ukraine, reversing the administration’s longstanding resistance to requests from Kyiv for the highly sophisticated but maintenance-heavy vehicles.
Biden said US Defense Secretary Lloyd Austin recommended the tank move because it will strengthen Ukraine's capacity to "defend its territory and achieve its strategic objectives."

"The Abrams tanks are the most capable tanks in the world. They're also extremely complex to operate and maintain, so we're also giving Ukraine the parts and equipment necessary to effectively sustain these tanks on the battlefield. We'll begin to train the Ukrainian troops on these issues of sustainment, logistics and maintenance as soon as possible," Biden said in remarks from the White House.
The Abrams will take months to arrive, senior administration officials said, and will require extensive training for Ukrainian troops on how to operate and service them. The US must navigate complicated supply chains for the components required for the tanks. 
"Delivering these tanks to the field is going to take time. Time that we'll see and we'll use to make sure the Ukrainians are fully prepared to integrate the Abrams tanks into their defenses," Biden added.
As recently as last week, top US officials didn't think that the Biden government will agree to providing the vehicles to Ukraine. 
Yet after series of diplomacy with Germany, who had made clear it would only send its Leopard 2 tanks to Ukraine if the United States offered up the Abrams, Biden has given the sign-off on sending the vehicles. The 31 Abrams will form a complete Ukrainian tank battalion. 
President Joe Biden said that the Ukraine Defense Contact Group members are also sending additional military equipment following their eighth meeting last week.

Biden also thanked the group of 50 nations that have so far contributed to Ukraine saying they are each making "significant contributions of their own to Ukraine's integrity."

"I want to thank every member of that coalition for continuing to step up," Biden added.
He said the following countries are sending military equipment and weapons:
United Kingdom: Donating Challenger 2 tanks to Ukraine.
France: Contributing AMX-10s, armored fighting vehicles and critical air defense systems.
Germany and United States: Leopard tanks and Patriot missile battery 
The Netherlands: Donating a Patriot missile and launchers 
Poland: Sending armored vehicles 
Sweden: Donating infantry fighting vehicles
Italy: Giving artillery 
Denmark and Estonia: Sending howitzers
Latvia: Providing for stinger missiles
Lithuania: Providing anti-aircraft guns
Finland: Announced its largest package of security assistance to date
Biden added, "France, Canada, the UK, Slovakia and Norway and others have all donated critical air defense systems to help secure Ukrainian skies and save the lives of innocent civilians who are literally the target — the target of Russia's aggression."